Sprint Filter P037 Air Filter for WorldSBK Racing – MV Agusta F3 800 (2012–2026) R135S-WP-SBK

Three versions of this kit exist for the F3, and this is the one bought for weather. R135S-WP-SBK carries the P037 medium: dry polyester with a water-repellent finish, rated at 37 µm and 4,500 l/m²/sec. Like its two siblings it is a carbon fibre framed assembly, and like them it requires the airbox to be modified and the element repositioned before it will fit. Unlike them, it is listed against the 800 alone.

Key Features

• P037 cloth: dry polyester with a water-repellent finish, 37 µm, rated 4,500 l/m²/sec
• WorldSBK-specification construction on a carbon fibre frame
• Fitting requires modification of the airbox and repositioning of the element
• Considerably tighter than the standard 80 µm weave, at a slightly lower rated flow
• Never oiled — regenerated with compressed air and washed when it needs more
• Two years of warranty from the date of purchase

The percentage that will not line up

Published figures put the P037 at 91.8 % retention and the standard P08 weave at 93.13 %. Read as a league table the P037 looks like the weaker filter, and that reading is simply wrong, because the two numbers come from different tests. The 93.13 % was measured against 100-micron particles. The 91.8 % was measured against 37-micron particles, which is a far harder thing to catch. A percentage is only comparable with another percentage from the same test, and these two are not. What can be set side by side is the specification: 37 µm against 80 µm, and 4,500 l/m²/sec against 5,050.

What water-repellent means, and what it does not

The finish belongs to the cloth. It resists water passing through the medium; it does not turn the airbox into a sealed vessel, and it is no substitute for an intact seal and a properly closed lid — filtration only ever applies to air that has actually gone through the material. Nor is it a performance feature in disguise: an element inside an airbox does not make a standard F3 800 noticeably stronger, and a wet-weather cloth least of all. What it addresses is a specific condition, on a machine ridden in it.

Care and cleaning

The water-repellent finish changes nothing about how R135S-WP-SBK is looked after. Compressed air from the clean side, blown outward, is the routine; hold the assembly by its carbon frame while you work. When a wet, gritty spell leaves deposits air will not shift, wash it in lukewarm water with a mild washing-up detergent and rinse until the run-off is clear. Then leave it in open air until it is dry the whole way through — no heat gun, no radiator, no flame, because heat destroys polyester regardless of what has been applied to it. It goes back in dry. The maintenance sheet is filed under Downloads.

Fitment & Compatibility

Listed for the airbox of the MV Agusta F3 800 built from 2012 to 2026, once that airbox has been modified to receive it. This is the only machine on the fitment list for this number; the P08 and F1-85 versions of the same kit each cover the 675 as well.